The invention relates generally to computer systems and, more particularly but not by way of limitation, to an improved motherboard apparatus for personal computer systems.
Personal computers are stand-alone computer systems housed in a chassis that may be conveniently placed on a user's desk or the floor next to the user's desk. Input/output (I/O) devices such as a video monitor, keyboard, mouse, and printer are typically coupled to the system by means of cables that plug into connectors at a back panel of the chassis. Inside the chassis is a system board, called a motherboard, that holds the electronic components of the computer. The computer system may have its capabilities enhanced through the use of expansion add-in cards. Add-in cards are generally inserted into slots that are mounted directly on the motherboard. The motherboard has printed circuit wiring that distributes signals from the add-in cards to appropriate components on the motherboard. There are currently two primary motherboard standards for personal computers: ATX and NLX. See the ATX (version 2.01, 1997) and NLX (version 1.2, 1997) specifications which are available from Intel Corporation.
Referring to FIG. 1, an ATX-based computer system 100 includes ATX motherboard 102 attached to chassis 104 at a number locations (indicated by filled circles 106 in FIG. 1). Motherboard 102 provides ISA (Industry Standard Architecture) slots 108, PCI (Peripheral Component Interconnect) slots 110, system memory slots 112, I/O connectors 114, processor receptacle 116, and floppy disk and IDE (Integrated Drive Electronics) connectors 118. As shown, ATX motherboard 102 is orientated in chassis 104 so that power supply unit 120 is proximally located to processor receptacle 116 and peripheral bays 122 and 124.
FIG. 2 shows a top view of a NLX-based computer system 200 that includes NLX motherboard 202, riser card connector 204, riser card 206, chassis 208, power supply 210, and expansion bay 212. Riser card connector 204 is a 340 pin riser connector. Motherboard 202 is coupled to chassis 208 by a rail mechanism (not shown) which allows it to be easily inserted and removed from chassis 208 as shown by arrow 214. Motherboard 202 provides I/O connectors 216 and processor receptacle 218, while riser card (and connector) provide add-in card slots and connectivity to other devices such as floppy disks and IDE devices. Use of riser card 206 allows all add-in card slots to be mounted parallel to motherboard 202.
While ATX-based computer system 100 provides a large expansion capability (through multiple add-in card slots), it is relatively difficult to manufacture and service because of the manner in which motherboard 102 is connected to chassis 104. While NLX-based computer system 200 provides a mechanism to easily assemble and service motherboard 202, it does not generally provide the expansion capability of an ATX-based computer system. It is therefore desirable to have an improved motherboard that may provide the expansion capability of an ATX-based computer system and the ease of manufacture and serviceability of a NLX-based computer system.